scholarly journals Inhaled Anesthetics Promote Albumin Dimerization through Reciprocal Exchange of Subdomains

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Benjamin J. Pieters ◽  
Eugene E. Fibuch ◽  
Joshua D. Eklund ◽  
Norbert W. Seidler
Keyword(s):  
Fluorescence Emission ◽  
Size Exclusion ◽  
Inhaled Anesthetics ◽  
Protein Protein Interaction ◽  
Reciprocal Exchange ◽  
Proposed Model ◽  
Exclusion Chromatography ◽  
Spectral Shifting ◽  
And Control ◽  
The Impact

Inhaled anesthetics affect protein-protein interaction, but the mechanisms underlying these effects are still poorly understood. We examined the impact of sevoflurane and isoflurane on the dimerization of human serum albumin (HSA), a protein with anesthetic binding sites that are well characterized. Intrinsic fluorescence emission was analyzed for spectral shifting and self-quenching, and control first derivatives (spectral responses to changes in HSA concentration) were compared against those obtained from samples treated with sevoflurane or isoflurane. Sevoflurane increased dimer-dependent self-quenching and both decreased oligomer-dependent spectral shifting, suggesting that inhaled anesthetics promoted HSA dimerization. Size exclusion chromatography and polarization data were consistent with these observations. The data support the proposed model of a reciprocal exchange of subdomains to form an HSA dimer. The open-ended exchange of subdomains, which we propose occuring in HSA oligomers, was inhibited by sevoflurane and isoflurane.

Kinetic and structural analysis of the ultrasensitive behaviour of cyanobacterial ADP-glucose pyrophosphorylase

2000 ◽  
Vol 350 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Diego F. GÓMEZ CASATI ◽  
Miguel A. AON ◽  
Alberto A. IGLESIAS
Keyword(s):  
Conformational Changes ◽  
Tertiary Structure ◽  
Fluorescence Emission ◽  
Maximal Activity ◽  
Size Exclusion ◽  
Exclusion Chromatography ◽  
Adp Glucose Pyrophosphorylase ◽  
Kinetics Of ◽  
Allosteric Regulators

The kinetic and (supra)molecular properties of the ultrasensitive behaviour of ADP-glucose pyrophosphorylase (AGPase) from Anabaena PCC 7120 (a cyanobacterium) were exhaustively studied. The response of the enzyme toward the allosteric activator 3-phosphoglycerate (3PGA) occurs with ultrasensitivity as a consequence of the cross-talk with the inhibitor Pi. Molecular ‘crowding’renders AGPase more sensitive to the interplay between the allosteric regulators and, consequently, enhances the ultrasensitive response. In crowded media, and when orthophosphate is present, the activation kinetics of the enzyme with 3PGA proceed with increased co-operativity and reduced affinity toward the activator. Under conditions of ultrasensitivity, the enzyme's maximal activation takes place in a narrow range of 3PGA concentrations. Moreover, saturation kinetics of the enzyme with respect to its substrates, glucose 1-phosphate and ATP, were different at low or high 3PGA levels in crowded media. Only under the latter conditions did AGPase exhibit discrimination between low or high levels of the activator, which increased the affinity toward the substrates and the maximal activity reached by the enzyme. Studies of fluorescence emission of tryptophan residues, fourth-derivative spectroscopy and size-exclusion chromatography indicated that the ultrasensitive behaviour is correlated with intramolecular conformational changes induced in the tertiary structure of the homotetrameric enzyme. The results suggest a physiological relevance of the ultrasensitive response of AGPase in vivo, since the enzyme could be subtly sensing changes in the levels of allosteric regulators and substrates, and thus determining the flux of metabolites toward synthesis of storage polysaccharides.

scholarly journals A Multistep Approach for Managing the Risks of Software Requirements Volatility

2016 ◽  
Vol 9 (1) ◽  
pp. 101
Author(s):  
Nedhal A. Al-Saiyd
Keyword(s):  
Software Requirements ◽  
Software Project ◽  
Font Size ◽  
Software Usability ◽  
Proposed Model ◽  
Requirements Volatility ◽  
And Control ◽  
Requirement Changes ◽  
The Impact

<p><span style="font-size: 10.5pt; font-family: 'Times New Roman','serif'; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;" lang="EN-US">Software is changed continuously in order to respond to different users and business needs. Requirements are changed dynamically to improve software usability and increase its value, but requirement volatility sometimes cause failures for many projects because of inadequate understanding of the changing causes and the consequences of these changes. This research highlights the importance of managing requirement changes, classify them, and control the impact risks of requirement volatility on software project. The proposed model is designed based on software requirements risks factors and how to reduce their impacts. Generally, requirements changing is considered as a difficult, costly and time-consumed task, and consequently it is too important to study the inter-relationships between the changes and their impacts on the other phases of software system. The good understanding of the changing causes and their consequences can improve and support requirements management process and also lead successfully to the predicted goals of changes. The high quality of the requirements influences the success of a software project during software development and maintenance processes.</span></p>

scholarly journals Impact of Botrytis cinerea Contamination on the Characteristics and Foamability of Yeast Macromolecules Released during the Alcoholic Fermentation of a Model Grape Juice

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 472
Author(s):  
Richard Marchal ◽  
Thomas Salmon ◽  
Ramon Gonzalez ◽  
Belinda Kemp ◽  
Céline Vrigneau ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Alcoholic Fermentation ◽  
Periodic Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Grape Juice ◽  
Size Exclusion ◽  
Periodic Acid Schiff ◽  
Exclusion Chromatography ◽  
The Impact

Botrytis cinerea is a fungal pathogen responsible for the decrease in foamability of sparkling wines. The proteolysis of must proteins originating from botrytized grapes is well known, but far less information is available concerning the effect of grape juice contamination by Botrytis. The impact from Botrytis on the biochemical and physico-chemical characteristics of proteins released from Saccharomyces during alcoholic fermentation remains elusive. To address this lack of knowledge, a model grape juice was inoculated with three enological yeasts with or without the Botrytis culture supernatant. Size exclusion chromatography coupled to multi-angle light scattering (SEC-MALLS) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) techniques (AgNO3 and periodic acid Schiff staining) was used in the study. When Botrytis enzymes were present, a significant degradation of the higher and medium MW molecules released by Saccharomyces was observed during alcoholic fermentation whilst the lower MW fraction increased. For the three yeast strains studied, the results clearly showed a strong decrease in the wine foamability when synthetic musts were inoculated with 5% (v/v) of Botrytis culture due to fungus proteases.

scholarly journals Assembly of the Complex between Archaeal RNase P Proteins RPP30 and Pop5

Archaea ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Brandon L. Crowe ◽  
Christopher J. Bohlen ◽  
Ross C. Wilson ◽  
Venkat Gopalan ◽  
Mark P. Foster
Keyword(s):  
Protein Interactions ◽  
Pyrococcus Furiosus ◽  
Resonance Assignments ◽  
Rnase P ◽  
Size Exclusion ◽  
Titration Calorimetry ◽  
Protein Protein Interaction ◽  
Model Complex ◽  
Exclusion Chromatography ◽  
P Proteins

RNase P is a highly conserved ribonucleoprotein enzyme that represents a model complex for understanding macromolecular RNA-protein interactions. Archaeal RNase P consists of one RNA and up to five proteins (Pop5, RPP30, RPP21, RPP29, and RPP38/L7Ae). Four of these proteins function in pairs (Pop5-RPP30 and RPP21–RPP29). We have used nuclear magnetic resonance (NMR) spectroscopy and isothermal titration calorimetry (ITC) to characterize the interaction between Pop5 and RPP30 from the hyperthermophilic archaeonPyrococcus furiosus(Pfu). NMR backbone resonance assignments of free RPP30 (25 kDa) indicate that the protein is well structured in solution, with a secondary structure matching that observed in a closely related crystal structure. Chemical shift perturbations upon the addition of Pop5 (14 kDa) reveal its binding surface on RPP30. ITC experiments confirm a net 1 : 1 stoichiometry for this tight protein-protein interaction and exhibit complex isotherms, indicative of higher-order binding. Indeed, light scattering and size exclusion chromatography data reveal the complex to exist as a 78 kDa heterotetramer with two copies each of Pop5 and RPP30. These results will inform future efforts to elucidate the functional role of the Pop5-RPP30 complex in RNase P assembly and catalysis.

scholarly journals Impact of Electron Beam Irradiation on Thermoplastic Polyurethanes Unraveled by Thermal Field-Flow Fractionation

2020 ◽  
Author(s):  
Martin Geisler ◽  
Tuhin Subhra Pal ◽  
Kerstin Arnhold ◽  
Mikhail Malanin ◽  
Michael Thomas Müller ◽  
...  
Keyword(s):  
Electron Beam ◽  
Size Exclusion Chromatography ◽  
Electron Beam Irradiation ◽  
Thermal Field ◽  
Size Exclusion ◽  
Field Flow Fractionation ◽  
Beam Irradiation ◽  
Exclusion Chromatography ◽  
Flow Fractionation ◽  
The Impact

The impact of electron beam irradiation on thermoplastic polyurethane material was studied for both an aliphatic and an aromatic polyurethane with equal amount of hard and soft segments. Irradiation doses up to 300 kGy at room temperature and at 100 °C were applied. Changes in chemical structure, molar mass and size were assessed using infrared spectroscopy, differential scanning calorimetry, size exclusion chromatography and thermal field flow fractionation. Material alterations were correlated with trends regarding to degradation, crosslinking or branching changes. Thereby, limits of characteri-zation by size exclusion chromatography are addressed and amended by thermal field-flow fractionation studies. In addition, a thermophoretic analysis has been carried out complementary to the portfolio of analytical methods applied in this work.

scholarly journals The GTPase Rab27b regulates the release, autophagic clearance, and toxicity of α-synuclein

2020 ◽  
Vol 295 (23) ◽  
pp. 8005-8016 ◽  
Author(s):  
Rachel Underwood ◽  
Bing Wang ◽  
Christine Carico ◽  
Robert H. Whitaker ◽  
William J. Placzek ◽  
...  
Keyword(s):  
Lewy Bodies ◽  
Neuronal Model ◽  
Primary Component ◽  
Size Exclusion ◽  
Autophagic Flux ◽  
Protein Levels ◽  
Exclusion Chromatography ◽  
Cell Release ◽  
The Impact

α-Synuclein (αsyn) is the primary component of proteinaceous aggregates termed Lewy bodies that pathologically define synucleinopathies including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). αsyn is hypothesized to spread through the brain in a prion-like fashion by misfolded protein forming a template for aggregation of endogenous αsyn. The cell-to-cell release and uptake of αsyn are considered important processes for its prion-like spread. Rab27b is one of several GTPases essential to the endosomal-lysosomal pathway and is implicated in protein secretion and clearance, but its role in αsyn spread has yet to be characterized. In this study, we used a paracrine αsyn in vitro neuronal model to test the impact of Rab27b on αsyn release, clearance, and toxicity. shRNA-mediated knockdown (KD) of Rab27b increased αsyn-mediated paracrine toxicity. Rab27b reduced αsyn release primarily through nonexosomal pathways, but the αsyn released after Rab27b KD was of higher-molecular-weight species, as determined by size-exclusion chromatography. Rab27b KD increased intracellular levels of insoluble αsyn and led to an accumulation of endogenous light chain 3 (LC3)-positive puncta. Rab27b KD also decreased LC3 turnover after treatment with an autophagosome-lysosome fusion inhibitor, chloroquine, indicating that Rab27b KD induces a defect in autophagic flux. Rab27b protein levels were increased in brain lysates obtained from postmortem tissues of individuals with PD and DLB compared with healthy controls. These data indicate a role for Rab27b in the release, clearance, and toxicity of αsyn and, ultimately, in the pathogenesis of synucleinopathies.

scholarly journals Role of COL3A1 and POSTN on Pathologic Stages of Esophageal Cancer

2020 ◽  
Vol 19 ◽  
pp. 153303382097748
Author(s):  
Shao-wei Zhang ◽  
Nan Zhang ◽  
Na Wang
Keyword(s):  
Gene Expression ◽  
Esophageal Cancer ◽  
Enrichment Analysis ◽  
Functional Enrichment Analysis ◽  
Gene Expression Omnibus ◽  
Functional Enrichment ◽  
Protein Protein Interaction ◽  
And Control ◽  
The Impact

Background: Esophageal cancer (EC) is a primary malignant tumor originating from the esophageal of the epithelium. Surgical resection is a potential treatment for EC, but this is only appropriate for patients who have locally resectable lesions suitable for surgery. However, most patients with EC are at a late stage when diagnosed. Therefore, there is an urgent need to further explore the pathogenesis of EC to enable early diagnosis and treatment. Methods: Our study downloaded 2 expression spectrum datasets (GSE92396 and GSE100942) in the Gene Expression Omnibus (GEO) database. GEO2 R was used to identify the Differentially expressed genes (DEGs) between the samples of EC and control. Using the DAVID tool to make the Functional enrichment analysis. Constructing A protein–protein interaction (PPI) network. Identifying the Hub genes. The impact of hub gene expression on overall survival and their expression based on immunohistochemistry were analyzed. Associated microRNAs were also predicted. Results: There were 36 common DEGs identified. The analysis of GO and KEGG results shown that the variations were predominantly concentrated in the extracellular matrix (ECM), ECM organization, DNA binding, platelet activation, and ECM-receptor interactions. COL3A1 and POSTN had high expression in EC tissues which was compared with their expression in healthy tissues. Analysis of pathologic stages showed that when COL3A1 and POSTN were highly expressed, the stage of the pathologic of EC patients was relatively high (P < 0.005). Conclusions: COL3A1 and POSTN may play an important role in the advancement and occurrence of EC. These genes could provide some novel ideas and basis for the diagnosis and targeted treatment of EC.

scholarly journals Processed Fruiting Bodies of Lentinus edodes as a Source of Biologically Active Polysaccharides

2020 ◽  
Vol 10 (2) ◽  
pp. 470 ◽  
Author(s):  
Marta Ziaja-Sołtys ◽  
Wojciech Radzki ◽  
Jakub Nowak ◽  
Jolanta Topolska ◽  
Ewa Jabłońska-Ryś ◽  
...  
Keyword(s):  
Biological Activities ◽  
Water Soluble ◽  
Biologically Active ◽  
Size Exclusion ◽  
Lentinus Edodes ◽  
Fruiting Bodies ◽  
Antioxidant Power ◽  
Exclusion Chromatography ◽  
Processing Techniques ◽  
The Impact

Water soluble polysaccharides (WSP) were isolated from Lentinus edodes fruiting bodies. The mushrooms were previously subjected to various processing techniques which included blanching, boiling, and fermenting with lactic acid bacteria. Therefore, the impact of processing on the content and biological activities of WSP was established. Non-processed fruiting bodies contained 10.70 ± 0.09 mg/g fw. Boiling caused ~12% decrease in the amount of WSP, while blanched and fermented mushrooms showed ~6% decline. Fourier transform infrared spectroscopy analysis (FTIR) confirmed the presence of β-glycosidic links, whereas due to size exclusion chromatography 216 kDa and 11 kDa molecules were detected. WSP exhibited antioxidant potential in FRAP (ferric ion reducing antioxidant power) and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assays. Cytotoxic properties were determined on MCF-7 and T47D human breast cell lines using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) test. Both biological activities decreased as the result of boiling and fermenting.

scholarly journals Medical Capacity Shortages Facilitated the Rapid Dissemination of COVID-19 in Wuhan, New York State, and Italy

2021 ◽  
Author(s):  
Yuehao Xu ◽  
Cheng Zhang ◽  
Lixian Qian
Keyword(s):  
New York ◽  
New York State ◽  
The United States ◽  
Policy Makers ◽  
York State ◽  
Proposed Model ◽  
Rapid Dissemination ◽  
City State ◽  
And Control ◽  
The Impact

Abstract Background: During the coronavirus disease 2019 (COVID-19) outbreak, every public health system faced the potential challenge of medical capacity shortages. Infections without timely diagnosis or treatment may facilitate the stealth transmission and spread of the virus. Important as the influence of capacity shortages on the epidemic, it is still unclear how they could intensify the spread of the epidemic qualitatively under different circumstances. Our study aims to throw light on this influence.Methods: Using infection and medical capacity information reported in Wuhan in China, New York State in the United States, and Italy, we developed a dynamic susceptible–exposed–infected–recovered (SEIR) model to estimate the impact of medical capacity shortages during the COVID-19 outbreak at the city, state, and country levels.Results: The proposed model can fit data well (R-square > 0.9). Through sensitivity analysis, we found that doubled capacity would lead to a 39% lower peak infected number in Wuhan. Italy and New York State have similar results.Conclusions: The less shortages in medical capacity, the faster decline in the daily infection numbers and the fewer deaths, and more shortage would lead to steepen infection curve. This study provides a method for estimating potential shortages and explains how they may dynamically facilitate disease spreading during future pandemics such as COVID-19. Based on this, policy makers may figure out some way to explore more medical capacity and control the epidemic better.

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